If you choose a top mounted smoke pipe, you better utilize the heat.
- A modern wood-burning stove has an efficiency of approx. 70%
- A stove with a nominal power of 8 kW will produce a power of 9 kW with a smoke pipe of 1 meter. This corresponds to an increase in power of 12.5%
- With a price of 90 SEK per 60 liter sack, the actual energy efficiency is 118 øre / kWh with rear mounted smoke pipe and 106 øre / kWh with top mounted pipes
- Wood burning for 12,000 kWh annually x 118 øre / kWh gives a total price per. year of 14,160 kr
- Wood burning for 12,000 kWh annually x 106 øre / kWh gives a total price per. year of 12,720 kr
- The gain by choosing one meter longer smoke pipe is then at 1440 SEK per year
– You must ignore the top
Bill. Dark: Dark and glowing
This shrinks the power bill
If you put your hand on the smoke pipe while firing in the oven, you burn. The smoke that passes out of the combustion chamber is 300 degrees.
With a top mounted smoke pipe, however, you can better utilize this heat.
– The extra heat achieved with top mounted smoke pipes equals up to 1 kW, says sales manager at Jøtul Group Accessories, Dan Frode Langebråten til Click. no.
Nevertheless, Norwegians choose the most rear mounted pipes.
– Norway is unique in European context. Otherwise, in Europe, using mostly piped pipes to maximize heat utilizes Langebråten.
Provides 12.5% more heat output
On behalf of clicks. no, Enova has calculated the difference in power between combustion in the furnace with top mounted versus rear mounted smoke pipe.
If 1 meter smoke pipe gives an extra power of 1 kW, furnaces with top mounted pipes provide 12.5% greater power than furnaces with rear mounted pipes (see the calculation in box t. h. ).
If you normally fire for 12,000 kWh a year, you will save over 1400 kroner each year on a long smoke pipe.
It corresponds to fifteen six-digit sacks of birch wood.
And the more you firing and the higher the price, the greater the savings when choosing a long smoke pipe.
The first meter warms the most
As the smoke pipes are not isolated, the smoke is cooled quickly. That means that there is little to gain from extending the tube yet another meter.
On the other hand, extra long smoke pipes can cause problems.
– Tubes above two meters can have a negative effect as the smoke gets so cooled that it can turn back into the room, Langebråten claims.
From rear mounted to top mounted
If you have already installed oven with rear mounted pipes, it is possible to convert to top mounted.
However, this is defined as a new installation and must therefore be approved by a qualified reviewer before use.
Requires proper firing
The benefit of mounting top pipes, according to Enova, may be less for the most advanced furnaces because they have significantly lower flue gas temperatures than slightly older furnaces.
– Therefore, there is reason to believe that there is some lesser effect here, says Trond Paasche, energy consultant at Enova Svar.
– I also think that the rule of thumb when it comes to power boost of 1 kW for one meter pipe does not apply to the smallest furnaces. They have smaller combustion chamber and therefore less power, “says the energy advisor.
Another prerequisite for achieving the profit the calculation assumes is that it is firing with high power throughout the season, which in practice is not common.
– The savings also depend on the heating being controlled so that one does not firing more power than necessary to achieve the desired indoor temperature, Enova explains.
Two types of pipes
Two different types of smoke pipes are used in Norway, painted and enamelled.
Painted pipes are the most expensive and most expensive. The surface is adapted to matt-painted fireplaces.
– But lacquer is also more vulnerable. The surface is easily scratched and can lose its color over time. It will also often rust inside, claims Langebråten in Jøtul Group Accessories.
– Enamelled pipes are significantly stronger. As they are actually enamelled inside, as opposed to the painted pipes, rust will not occur.
Traditionally, the enamel has been blank and thus not adapted to matt-painted fireplaces. Today, however, there are pipes with matt enamel that fits well with fireplaces with matt paint.
Straight, short tube for rear mounting gets you for 200-300 crowns, while longer pipes with fully bent bend goes for 1800 crowns and upwards.
If you use a rectangular tube you can feel that the smoke is prevented and that it is harder to ignite the oven. Ideally, the top mounted tube has a fully bent bend of 90 degrees. Then the smoke runs best through the pipe, says Langebråten.
And on its way to pipes, the smoke causes the pipe to heat up as much as a 1000 watts panel oven.
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